1 //===-- ObjCLanguageRuntime.h -----------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLDB_SOURCE_PLUGINS_LANGUAGERUNTIME_OBJC_OBJCLANGUAGERUNTIME_H
10 #define LLDB_SOURCE_PLUGINS_LANGUAGERUNTIME_OBJC_OBJCLANGUAGERUNTIME_H
11 
12 #include <functional>
13 #include <map>
14 #include <memory>
15 #include <unordered_set>
16 
17 #include "llvm/Support/Casting.h"
18 
19 #include "lldb/Breakpoint/BreakpointPrecondition.h"
20 #include "lldb/Core/PluginInterface.h"
21 #include "lldb/Core/ThreadSafeDenseMap.h"
22 #include "lldb/Symbol/CompilerType.h"
23 #include "lldb/Symbol/Type.h"
24 #include "lldb/Target/LanguageRuntime.h"
25 #include "lldb/lldb-private.h"
26 
27 class CommandObjectObjC_ClassTable_Dump;
28 
29 namespace lldb_private {
30 
31 class TypeSystemClang;
32 class UtilityFunction;
33 
34 class ObjCLanguageRuntime : public LanguageRuntime {
35 public:
36   enum class ObjCRuntimeVersions {
37     eObjC_VersionUnknown = 0,
38     eAppleObjC_V1 = 1,
39     eAppleObjC_V2 = 2
40   };
41 
42   typedef lldb::addr_t ObjCISA;
43 
44   class ClassDescriptor;
45   typedef std::shared_ptr<ClassDescriptor> ClassDescriptorSP;
46 
47   // the information that we want to support retrieving from an ObjC class this
48   // needs to be pure virtual since there are at least 2 different
49   // implementations of the runtime, and more might come
50   class ClassDescriptor {
51   public:
52     ClassDescriptor()
53         : m_is_kvo(eLazyBoolCalculate), m_is_cf(eLazyBoolCalculate),
54           m_type_wp() {}
55 
56     virtual ~ClassDescriptor() = default;
57 
58     virtual ConstString GetClassName() = 0;
59 
60     virtual ClassDescriptorSP GetSuperclass() = 0;
61 
62     virtual ClassDescriptorSP GetMetaclass() const = 0;
63 
64     // virtual if any implementation has some other version-specific rules but
65     // for the known v1/v2 this is all that needs to be done
66     virtual bool IsKVO() {
67       if (m_is_kvo == eLazyBoolCalculate) {
68         const char *class_name = GetClassName().AsCString();
69         if (class_name && *class_name)
70           m_is_kvo =
71               (LazyBool)(strstr(class_name, "NSKVONotifying_") == class_name);
72       }
73       return (m_is_kvo == eLazyBoolYes);
74     }
75 
76     // virtual if any implementation has some other version-specific rules but
77     // for the known v1/v2 this is all that needs to be done
78     virtual bool IsCFType() {
79       if (m_is_cf == eLazyBoolCalculate) {
80         const char *class_name = GetClassName().AsCString();
81         if (class_name && *class_name)
82           m_is_cf = (LazyBool)(strcmp(class_name, "__NSCFType") == 0 ||
83                                strcmp(class_name, "NSCFType") == 0);
84       }
85       return (m_is_cf == eLazyBoolYes);
86     }
87 
88     virtual bool IsValid() = 0;
89 
90     /// There are two routines in the ObjC runtime that tagged pointer clients
91     /// can call to get the value from their tagged pointer, one that retrieves
92     /// it as an unsigned value and one a signed value.  These two
93     /// GetTaggedPointerInfo methods mirror those two ObjC runtime calls.
94     /// @{
95     virtual bool GetTaggedPointerInfo(uint64_t *info_bits = nullptr,
96                                       uint64_t *value_bits = nullptr,
97                                       uint64_t *payload = nullptr) = 0;
98 
99     virtual bool GetTaggedPointerInfoSigned(uint64_t *info_bits = nullptr,
100                                             int64_t *value_bits = nullptr,
101                                             uint64_t *payload = nullptr) = 0;
102     /// @}
103 
104     virtual uint64_t GetInstanceSize() = 0;
105 
106     // use to implement version-specific additional constraints on pointers
107     virtual bool CheckPointer(lldb::addr_t value, uint32_t ptr_size) const {
108       return true;
109     }
110 
111     virtual ObjCISA GetISA() = 0;
112 
113     // This should return true iff the interface could be completed
114     virtual bool
115     Describe(std::function<void(ObjCISA)> const &superclass_func,
116              std::function<bool(const char *, const char *)> const
117                  &instance_method_func,
118              std::function<bool(const char *, const char *)> const
119                  &class_method_func,
120              std::function<bool(const char *, const char *, lldb::addr_t,
121                                 uint64_t)> const &ivar_func) const {
122       return false;
123     }
124 
125     lldb::TypeSP GetType() { return m_type_wp.lock(); }
126 
127     void SetType(const lldb::TypeSP &type_sp) { m_type_wp = type_sp; }
128 
129     struct iVarDescriptor {
130       ConstString m_name;
131       CompilerType m_type;
132       uint64_t m_size;
133       int32_t m_offset;
134     };
135 
136     virtual size_t GetNumIVars() { return 0; }
137 
138     virtual iVarDescriptor GetIVarAtIndex(size_t idx) {
139       return iVarDescriptor();
140     }
141 
142   protected:
143     bool IsPointerValid(lldb::addr_t value, uint32_t ptr_size,
144                         bool allow_NULLs = false, bool allow_tagged = false,
145                         bool check_version_specific = false) const;
146 
147   private:
148     LazyBool m_is_kvo;
149     LazyBool m_is_cf;
150     lldb::TypeWP m_type_wp;
151   };
152 
153   class EncodingToType {
154   public:
155     virtual ~EncodingToType();
156 
157     virtual CompilerType RealizeType(TypeSystemClang &ast_ctx, const char *name,
158                                      bool for_expression) = 0;
159     virtual CompilerType RealizeType(const char *name, bool for_expression);
160 
161   protected:
162     std::unique_ptr<TypeSystemClang> m_scratch_ast_ctx_up;
163   };
164 
165   class ObjCExceptionPrecondition : public BreakpointPrecondition {
166   public:
167     ObjCExceptionPrecondition();
168 
169     ~ObjCExceptionPrecondition() override = default;
170 
171     bool EvaluatePrecondition(StoppointCallbackContext &context) override;
172     void GetDescription(Stream &stream, lldb::DescriptionLevel level) override;
173     Status ConfigurePrecondition(Args &args) override;
174 
175   protected:
176     void AddClassName(const char *class_name);
177 
178   private:
179     std::unordered_set<std::string> m_class_names;
180   };
181 
182   static lldb::BreakpointPreconditionSP
183   GetBreakpointExceptionPrecondition(lldb::LanguageType language,
184                                      bool throw_bp);
185 
186   class TaggedPointerVendor {
187   public:
188     virtual ~TaggedPointerVendor() = default;
189 
190     virtual bool IsPossibleTaggedPointer(lldb::addr_t ptr) = 0;
191 
192     virtual ObjCLanguageRuntime::ClassDescriptorSP
193     GetClassDescriptor(lldb::addr_t ptr) = 0;
194 
195   protected:
196     TaggedPointerVendor() = default;
197 
198   private:
199     TaggedPointerVendor(const TaggedPointerVendor &) = delete;
200     const TaggedPointerVendor &operator=(const TaggedPointerVendor &) = delete;
201   };
202 
203   ~ObjCLanguageRuntime() override;
204 
205   static char ID;
206 
207   bool isA(const void *ClassID) const override {
208     return ClassID == &ID || LanguageRuntime::isA(ClassID);
209   }
210 
211   static bool classof(const LanguageRuntime *runtime) {
212     return runtime->isA(&ID);
213   }
214 
215   static ObjCLanguageRuntime *Get(Process &process) {
216     return llvm::cast_or_null<ObjCLanguageRuntime>(
217         process.GetLanguageRuntime(lldb::eLanguageTypeObjC));
218   }
219 
220   virtual TaggedPointerVendor *GetTaggedPointerVendor() { return nullptr; }
221 
222   typedef std::shared_ptr<EncodingToType> EncodingToTypeSP;
223 
224   virtual EncodingToTypeSP GetEncodingToType();
225 
226   virtual ClassDescriptorSP GetClassDescriptor(ValueObject &in_value);
227 
228   ClassDescriptorSP GetNonKVOClassDescriptor(ValueObject &in_value);
229 
230   virtual ClassDescriptorSP
231   GetClassDescriptorFromClassName(ConstString class_name);
232 
233   virtual ClassDescriptorSP GetClassDescriptorFromISA(ObjCISA isa);
234 
235   ClassDescriptorSP GetNonKVOClassDescriptor(ObjCISA isa);
236 
237   lldb::LanguageType GetLanguageType() const override {
238     return lldb::eLanguageTypeObjC;
239   }
240 
241   virtual bool IsModuleObjCLibrary(const lldb::ModuleSP &module_sp) = 0;
242 
243   virtual bool ReadObjCLibrary(const lldb::ModuleSP &module_sp) = 0;
244 
245   virtual bool HasReadObjCLibrary() = 0;
246 
247   lldb::addr_t LookupInMethodCache(lldb::addr_t class_addr, lldb::addr_t sel);
248 
249   void AddToMethodCache(lldb::addr_t class_addr, lldb::addr_t sel,
250                         lldb::addr_t impl_addr);
251 
252   TypeAndOrName LookupInClassNameCache(lldb::addr_t class_addr);
253 
254   void AddToClassNameCache(lldb::addr_t class_addr, const char *name,
255                            lldb::TypeSP type_sp);
256 
257   void AddToClassNameCache(lldb::addr_t class_addr,
258                            const TypeAndOrName &class_or_type_name);
259 
260   lldb::TypeSP LookupInCompleteClassCache(ConstString &name);
261 
262   llvm::Optional<CompilerType> GetRuntimeType(CompilerType base_type) override;
263 
264   virtual llvm::Expected<std::unique_ptr<UtilityFunction>>
265   CreateObjectChecker(std::string name, ExecutionContext &exe_ctx) = 0;
266 
267   virtual ObjCRuntimeVersions GetRuntimeVersion() const {
268     return ObjCRuntimeVersions::eObjC_VersionUnknown;
269   }
270 
271   bool IsValidISA(ObjCISA isa) {
272     UpdateISAToDescriptorMap();
273     return m_isa_to_descriptor.count(isa) > 0;
274   }
275 
276   virtual void UpdateISAToDescriptorMapIfNeeded() = 0;
277 
278   void UpdateISAToDescriptorMap() {
279     if (m_process && m_process->GetStopID() != m_isa_to_descriptor_stop_id) {
280       UpdateISAToDescriptorMapIfNeeded();
281     }
282   }
283 
284   virtual ObjCISA GetISA(ConstString name);
285 
286   virtual ObjCISA GetParentClass(ObjCISA isa);
287 
288   // Finds the byte offset of the child_type ivar in parent_type.  If it can't
289   // find the offset, returns LLDB_INVALID_IVAR_OFFSET.
290 
291   virtual size_t GetByteOffsetForIvar(CompilerType &parent_qual_type,
292                                       const char *ivar_name);
293 
294   bool HasNewLiteralsAndIndexing() {
295     if (m_has_new_literals_and_indexing == eLazyBoolCalculate) {
296       if (CalculateHasNewLiteralsAndIndexing())
297         m_has_new_literals_and_indexing = eLazyBoolYes;
298       else
299         m_has_new_literals_and_indexing = eLazyBoolNo;
300     }
301 
302     return (m_has_new_literals_and_indexing == eLazyBoolYes);
303   }
304 
305   void SymbolsDidLoad(const ModuleList &module_list) override {
306     m_negative_complete_class_cache.clear();
307   }
308 
309   bool GetTypeBitSize(const CompilerType &compiler_type,
310                       uint64_t &size) override;
311 
312   /// Check whether the name is "self" or "_cmd" and should show up in
313   /// "frame variable".
314   bool IsAllowedRuntimeValue(ConstString name) override;
315 
316 protected:
317   // Classes that inherit from ObjCLanguageRuntime can see and modify these
318   ObjCLanguageRuntime(Process *process);
319 
320   virtual bool CalculateHasNewLiteralsAndIndexing() { return false; }
321 
322   bool ISAIsCached(ObjCISA isa) const {
323     return m_isa_to_descriptor.find(isa) != m_isa_to_descriptor.end();
324   }
325 
326   bool AddClass(ObjCISA isa, const ClassDescriptorSP &descriptor_sp) {
327     if (isa != 0) {
328       m_isa_to_descriptor[isa] = descriptor_sp;
329       return true;
330     }
331     return false;
332   }
333 
334   bool AddClass(ObjCISA isa, const ClassDescriptorSP &descriptor_sp,
335                 const char *class_name);
336 
337   bool AddClass(ObjCISA isa, const ClassDescriptorSP &descriptor_sp,
338                 uint32_t class_name_hash) {
339     if (isa != 0) {
340       m_isa_to_descriptor[isa] = descriptor_sp;
341       m_hash_to_isa_map.insert(std::make_pair(class_name_hash, isa));
342       return true;
343     }
344     return false;
345   }
346 
347 private:
348   // We keep a map of <Class,Selector>->Implementation so we don't have to call
349   // the resolver function over and over.
350 
351   // FIXME: We need to watch for the loading of Protocols, and flush the cache
352   // for any
353   // class that we see so changed.
354 
355   struct ClassAndSel {
356     ClassAndSel() {
357       sel_addr = LLDB_INVALID_ADDRESS;
358       class_addr = LLDB_INVALID_ADDRESS;
359     }
360 
361     ClassAndSel(lldb::addr_t in_sel_addr, lldb::addr_t in_class_addr)
362         : class_addr(in_class_addr), sel_addr(in_sel_addr) {}
363 
364     bool operator==(const ClassAndSel &rhs) {
365       if (class_addr == rhs.class_addr && sel_addr == rhs.sel_addr)
366         return true;
367       else
368         return false;
369     }
370 
371     bool operator<(const ClassAndSel &rhs) const {
372       if (class_addr < rhs.class_addr)
373         return true;
374       else if (class_addr > rhs.class_addr)
375         return false;
376       else {
377         if (sel_addr < rhs.sel_addr)
378           return true;
379         else
380           return false;
381       }
382     }
383 
384     lldb::addr_t class_addr;
385     lldb::addr_t sel_addr;
386   };
387 
388   typedef std::map<ClassAndSel, lldb::addr_t> MsgImplMap;
389   typedef std::map<ObjCISA, ClassDescriptorSP> ISAToDescriptorMap;
390   typedef std::multimap<uint32_t, ObjCISA> HashToISAMap;
391   typedef ISAToDescriptorMap::iterator ISAToDescriptorIterator;
392   typedef HashToISAMap::iterator HashToISAIterator;
393   typedef ThreadSafeDenseMap<void *, uint64_t> TypeSizeCache;
394 
395   MsgImplMap m_impl_cache;
396   LazyBool m_has_new_literals_and_indexing;
397   ISAToDescriptorMap m_isa_to_descriptor;
398   HashToISAMap m_hash_to_isa_map;
399   TypeSizeCache m_type_size_cache;
400 
401 protected:
402   uint32_t m_isa_to_descriptor_stop_id;
403 
404   typedef std::map<ConstString, lldb::TypeWP> CompleteClassMap;
405   CompleteClassMap m_complete_class_cache;
406 
407   struct ConstStringSetHelpers {
408     size_t operator()(ConstString arg) const // for hashing
409     {
410       return (size_t)arg.GetCString();
411     }
412     bool operator()(ConstString arg1,
413                     ConstString arg2) const // for equality
414     {
415       return arg1.operator==(arg2);
416     }
417   };
418   typedef std::unordered_set<ConstString, ConstStringSetHelpers,
419                              ConstStringSetHelpers>
420       CompleteClassSet;
421   CompleteClassSet m_negative_complete_class_cache;
422 
423   ISAToDescriptorIterator GetDescriptorIterator(ConstString name);
424 
425   friend class ::CommandObjectObjC_ClassTable_Dump;
426 
427   std::pair<ISAToDescriptorIterator, ISAToDescriptorIterator>
428   GetDescriptorIteratorPair(bool update_if_needed = true);
429 
430   void ReadObjCLibraryIfNeeded(const ModuleList &module_list);
431 
432   ObjCLanguageRuntime(const ObjCLanguageRuntime &) = delete;
433   const ObjCLanguageRuntime &operator=(const ObjCLanguageRuntime &) = delete;
434 };
435 
436 } // namespace lldb_private
437 
438 #endif // LLDB_SOURCE_PLUGINS_LANGUAGERUNTIME_OBJC_OBJCLANGUAGERUNTIME_H
439